The invention relates to injector cartridges for intraocular lens injection into an eye of a patient, and more specifically to methods for improving the wettability of hydrophobic plastic surfaces of medical devices without providing or forming a separate coating of a lubricious agent on the surface of the medical device.
The human eye in its simplest terms functions to provide vision by transmitting and refracting light through a clear outer portion called the cornea, and further focusing the image by way of lens onto the retina at the back of the eye. The quality of the focused image depends on many factors including the size, shape and length of the eye, and the shape and transparency of the cornea and lens.
When trauma, age or disease cause the lens to become less transparent, vision deteriorates because of the diminished light which can be transmitted to the retina. This deficiency in the lens of the eye is medically known as a cataract. The treatment for this condition is surgical removal of the lens and implantation of an intraocular lens (IOL).
While early IOLs were made from hard plastic, such as polymethylmethacrylate (PMMA), soft foldable IOLs made from silicone, soft acrylics and hydrogels have become increasingly popular because of the ability to fold or roll these soft lenses and insert them through a smaller incision. Several methods of rolling or folding the lenses are used. One popular method is an injector cartridge that folds the lenses and provides a relatively small diameter lumen through which the lens may be pushed into the eye, usually by a soft tip plunger. Commonly used injector cartridge design are illustrated in, for example, U.S. Pat. No. 4,681,102 (Bartell), U.S. Pat. Nos. 5,494,484 and 5,499,987 (Feingold) and U.S. Pat. Nos. 5,616,148 and 5,620,450 (Eagles, et al.), the entire contents of which are incorporated herein by reference.
One problem that exists for typical currently available cartridges is that the IOL may stick to the inner surface of the cartridge when the an attempt is made to inject the IOL into an eye by moving the lens along a pathway in the cartridge that is configured to fold the lens as it traverses the pathway from a position where the lens is unfolded to the nozzle of the injector for insertion into the eye. In some cases, viscoelastic material is inserted into the injector prior to pushing the lens through the lens delivery and folding pathway. In other case, the surface of the injector is modified in some fashion so as to render it more lubricious. For example, an additive may be added to the material from which the injector is formed to provide lubricity.
Alternatively, a lubricious coating may be added to the interior surface of the injector. However, such a coating may transfer to the lens and being carried into the eye. Additionally, most coating cannot retain their lubricity and physical integrity during steam sterilization in the presence of water, or avoid generating particles or dissolved coating which contaminates the storage media in which the lens is stored after packaging.
Accordingly, what has been needed and heretofore unavailable is a lens cartridge that can be modified to attain an essentially permanent increase in lubricity to facilitate implantation of an IOL into the eye. Such a modification would be stable in the presence of a storage media, and would be able to withstand steam sterilization, particularly where the modification is applied to a cartridge in which a lens is loaded, an aqueous storage media is added to the cartridge to maintain the lens in an aqueous medium, and then the entire package is steam sterilized. In this manner the IOL injector cartridge may also be used as a shipping case. The present invention fulfills these, and other needs.